Hazardous

Materials Assessment

LEAD

General Information

Lead is a naturally occurring element found in nature in the form of ores; it is a heavy, soft, malleable bluish metal. The history of it's use traces back many centuries. The oldest known lead object was a statue excavated in Turkey and dated somewhere around 6500 B.C. During the Roman Empire, lead was used extensively in many aspects of life; to line vessels that stored water and wine, in utensils, and, in combined form, as a glaze on pottery.

In more recent years lead was widely used to extend the protective properties of paints, helped automobiles attain better fuel efficiency, protected occupationally exposed workers from harmful radiation and provided a suitably dense material for ammunition, and fishing weights. Even though it is no longer used in many of these applications, millions of homes remain painted with lead paint. It's been estimated that approximately 94% of the residential housing in San Francisco was built prior to 1978 and probably has lead-based paint. Lead-based paint chips, as well as soil and household dust contaminated with lead are the primary sources of childhood lead poisoning.

Lead carbonate (white lead):

white pigment most commonly used in house paint.

Lead Acetate:

commonly used in paint, varnish and other coatings.

Lead oxide (red lead):

commonly used as primer on steel to prevent corrosion.

Gray or Blue Lead:

commonly used on ships for corrosion control

Lead Chromate:

commonly used on highways, parking structures, etc.

Types of Paints & Coating:

Lead Content in Paints:

In the late 1950's, paint manufacturers voluntarily reduced lead content of most paint for residential use to 1/2 of 1% (5000 ppm).
In the late '70's, EPA regulated Lead-Based Paint for residential usage, defined as paints with greater than 0.5% lead (5000 ppm).